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At least 145 records · Page 8Linked to original sources
PubMed1985

Improvement of bioavailability of poorly absorbed drugs. II. Effect of medium chain glyceride base on the intestinal absorption of cefmetazole sodium in rats and dogs.

The effect of medium chain glyceride (MCG) on the intestinal absorption of cefmetazole sodium (CMZ) was investigated in rats and dogs. In rats, MCG containing glyceryl mono-, di- and tri-caprylate enhanced the intestinal absorption of CMZ after intraduodenal administration, though the promoting effect of MCG was less than that after rectal administration. The promoting effect of MCG was found to be mainly due to glycerylmonocaprylate and dependent on the dosage of MCG. The plasma CMZ levels after intraduodenal administration as MCG solution tended to be slightly higher than those observed after administration as MCG emulsion, though the differences were found to be statistically insignificant. Moreover, the intestinal absorption of CMZ after intraduodenal administration as MCG emulsion was decreased significantly by increasing the amount of water in the emulsion. The promoting effect of MCG in dogs was more clearly demonstrated in the lower intestine than in the upper intestine. Furthermore, the oral bioavailability of pharmaceutical formulations of CMZ was also investigated in dogs. When enteric coated capsules filled with MCG solution were administered to dogs, the bioavailability of CMZ was enhanced significantly.

Animals↗
PubMed1984

Synthesis, intestinal absorption and metabolism of sarcosine conjugated ursodeoxycholic acid.

Sarcosine conjugated ursodeoxycholic acid (SUDC) was synthesized and its intestinal absorption and metabolism were studied in rat and hamster. Intestinal absorption study using bile fistula rat shows that more than 90% of SUDC administered intraduodenally was excreted in the bile within 24 hr. No change of the administered bile acid was seen during the absorption from the intestine, the passage of the liver, and the excretion into the bile. When [24-14C]SUDC and [11,12-3H2]-ursodeoxycholic acid were administered orally to a hamster, more than 95% of both the administered 14C and 3H were recovered from the feces within 6 days. Most (77%) of the fecal 14C-labeled compound was SUDC, whereas 95% of the fecal 3H-labeled compound was unconjugated lithocholic acid. These results indicate that SUDC, unlike taurine or glycine conjugated bile acid, resists bacterial deconjugation and 7-dehydroxylation.

Animals↗
PubMed1979

Determinants of the rate of intestinal absorption of oral cholecystographic contrast agents in the dog jejunum.

Successful opacification of the gallbladder during oral cholecystography depends on adequate absorption of the contrast agent from the intestine. The present studies were undertaken to define the specific characteristics of the intestinal mucosa and the properties of the various contrast agents which determine their rates of intestinal absorption. The polarity of the compounds was established by determining the ratios of their distribution between bulk solvents (benzene and water). In addition, the maximum aqueous solubility of each compound was determined. Using in vivo cannulated segments of dog jejunum, apparent passive permeability coefficients were measured. From these data, the apparent maximal rate of intestinal absorption was calculated. The six cholecystopaques studied differed markedly in polarity as judged by their varying ratios of distribution between benzene and water. The permeability coefficients varied inversely with the polarity of the compounds. However, the incremental changes in the coefficients were considerably less than the corresponding changes observed in the partition ratios. The rates of absorption of the more polar contrast agents (tyropanoate, iopronic acid, and iocetamic acid) were greater than the less polar compounds (iopanoic acid, sodium ipodate, and calcium ipodate) under the conditions in which the resistance of the unstirred water layer is not rate limiting and where bile acid micelles are not present.

Animals↗
PubMed1978

Intestinal absorption and tissue retention of cadmium and calcium in normal adult rats and rats given an active metabolite of vitamin D (1,25-dihydroxycholecalciferol).

1. Nine-months-old male rats were divided into a normal control group and one experimental group which received eight daily intraperitoneal injections 15 pmol of 1,25-dihydroxycholecalciferol/100 g body weight. After 5 days, 20 muCi of 109CdCl2 or 20muCi of 45CaCl2 was administered by stomach tube. The intestinal absorption and tissue retention of the radioisotopes were analysed during the next 3 days, the animals being kept in metabolic cages. 2. The administration of 1,25-dihydroxycholecalciferol caused significantly increased net absorption of intestinal calcium, hypercalcaemia and increased incorporation of calcium into bone. In comparison, there was no significant effect on the intestinal absorption of trace doses of cadmium or upon the accumulation of cadmium in the liver and kidneys.

Animals↗
PubMedDate not supplied

Isolation, chemical characterization, and immunohistochemical localization of a protein from the basolateral plasma membrane of the rat intestinal absorptive cell.

The protein pattern of the basolateral membrane (BLM) of the rat small intestinal absorptive cell shows about 20 major and a multitude of minor bands. A simple and efficient method is described for isolation and purification of a major protein in the 17 kDa molecular weight (MW)-range called Prot 17. The isolated BLM of intestinal epithelial cells was dissolved in buffer 1 (Tris/HCl, 2% SDS, 10% glycerol, 5% beta-mercaptoethanol, pH 6.8) and subsequently dialyzed for 4 h against buffer 2 (Tris/glycine, pH 8.3) and then for 12 h against buffer 2 containing 25% methanol. The resulting precipitate contained Prot 17 and phospholipids in the form of liposomes. All other BLM proteins remained dissolved in the supernatant. Chemical characterization of Prot 17 suggested that it is an integral membrane protein amounting to about 5% of the total BLM protein. Amino acid analysis revealed a MW of 17.6 kDa. The Prot 17 molecule did not contain any PAS-positive carbohydrates. In its isolated form, and apparently also in the BLM, Prot 17 occurred as a polymerized structure with a MW of about 90 kDa. By dissolution in buffer 1 and heating to 100 degrees C for 1 min the complex was split into its 17 kDa subunits. By oxidation with performic acid it was also broken down into its subunits. A specific antiserum against Prot 17 was obtained from immunized Balb/c mice. Immunofluorescence labelling of rat small intestinal sections with this serum showed that Prot 17 was not a BLM-specific protein. It occurred in both plasma membrane domains of the intestinal absorptive cell.

Animals↗
PubMed1986

Intestinal absorption of 5-fluorouracil and its alkylcarbamoyl derivatives in the rat small intestine.

The intestinal absorption of 5-fluorouracil (1) and its alkylcarbamoyl derivatives possessing various lipophilic pro-moieties including the butylcarbamoyl, hexylcarbamoyl, octylcarbamoyl, and nonylcarbamoyl groups, was investigated in the rat using both in situ and in vitro techniques. All compounds showed greater apparent partition coefficients and lipophilic indices (k') (by HPLC) and lower solubilities in water than 1. Although enhancement of uptake by the everted intestine in vitro was observed when the alkylcarbamoyl chain length was increased, the appearance of the prodrugs in the mesenteric vein in the in situ intestinal loop (complete venous collection) was decreased and sustained. The conversion of alkylcarbamoyl derivatives to 1 was noted in the absorption process.

Animals↗
PubMed1987

The effect of di- and trivalent iron on the intestinal absorption of aluminum in rats.

The effect of iron (Fe) on the intestinal absorption of aluminum (A1) was studied in an in situ perfusion system of rat small intestine in combination with systemic and portal blood sampling. The gut was perfused with media containing 0.0, 10.0, 15.0, 20.0, and 25.0 mmol/liter Al chloride and 5 mmol/liter Fe(II) or Fe(III) chloride at pH 3.0. Neither luminal disappearance nor intestinal absorption of A1 were affected by Fe(III). Fe(II), however, enhanced luminal disappearance and reduced absorption of Al.

Aluminum↗
PubMed1986

Intestinal absorption of folic acid, glucose, sodium and water in chronic pancreatitis.

Intestinal absorption of folic acid, glucose, water and sodium in 10 patients with chronic pancreatitis who have abstained from alcohol for at least 2 months is compared with 18 agematched outpatients without gastrointestinal disorders and a daily alcohol intake less than 30 g. Intestinal absorption was measured by segmental perfusion of the jejunum using a triple lumen tube. Patients with chronic pancreatitis showed a significantly decreased absorption of folic acid and glucose, whereas the net absorption of water and sodium was not disturbed.

Adult↗
PubMed1984

[Functional diagnosis of intestinal absorption in gastroenterology surgery].

Clinical tests for measuring the intestinal absorption in abdominal surgery, especially surgery of the GI-tract, are of great importance. The absorption of the proximal small intestine can be investigated via a modified D-xylose-test. The distal small intestine may be studied by using the vitamin-B12 urinary excretion test. The bacterial overgrowth syndrome and the absorption of bile salts can be diagnosed on the basis of a 14C-glykocholate test.

Biopsy↗
PubMed1975

Electron microscope autoradiographic study of intestinal absorption of decanoic and octanoic acids in the rat.

Intestinal absorption of [3H]octanoic acid and [3H]decanoic acid was investigated in the rat by electron microscope autoradiography. The common duct (bile and pancreatic common duct) of the rats was diverted and a loop of the duodenum was cannulated 24 h later. The lipid mixture to be investigated was introduced into each experimental loop, and after 15 min or less the loop was removed. One part of each loop was used to determine the distribution of radioactivity in different lipid fractions, and an autoradiographic study was performed on the other part of the loop. Radioactivity distribution studies confirmed that medium chain fatty acids are absorbed in their nonesterified form and established that these fatty acids are absorbed much more rapidly than oleic acid. Autoradiographic studies indicated that the medium chain fatty acids are taken up in a molecular or aggregate molecular form, leave the epithelial cells by way of the lateral plasma membrane, and are next found in the blood capillaries. Our results suggest that the Golgi complex does not play an important role in the absorption of unesterified fatty acids.

Animals↗
PubMed1982

[Kinetics of intestinal absorption in cases of dumping syndrome following partial gastrectomy and pyloric stenosis (author's transl)].

By means of analyses of intestinal absorption using the modified D-Xylose test the absorption kinetics of nutrients in cases of dumping syndrome after partial gastrectomy and in cases of pyloric stenosis could be traced. There was no decrease of absorption in the small gut. Changes of the intestinal absorption in cases of gastric dumping were caused by rapid gastric emptying. The delayed gastric emptying in cases of pyloric stenosis is followed by a decrease of Xylose resorption due to the reduction of resorption. The D-Xylose-test allows disorders of gastric emptying to be differentiated from those of enteral resorption.

Adult↗
PubMed1987

[Comparison of 2 technics (ninhydrin vs. TNSB) for estimating circulating amino acid nitrogen, applied to the study of the intestinal absorption of solutions of free amino acids or small peptides].

The intestinal absorption of nitrogen from amino acids present in a solution of small peptides or of free amino acids with the same pattern, perfused intraduodenally, has been studied using two analytical techniques [2, 4, 6 trinitrobenzene-1-sulfonic acid (TNBS) after dialysis of the blood vs ninhydrine after chromatography] to determine post-perfusion porto arterial differences and to measure blood flow rate in the portal vein. The results obtained on blood nitrogen level with the chromatographic method were always higher than those obtained using the TNBS method. The differences in the values varied from 8 to 24% according to post-perfusion time and to blood sample origin (arterial or portal). On the contrary, the absorbed amounts of nitrogen measured by either analytical technique were not very much different: no significant and systematic deviation was found between the two. The TNBS method is thus useful as a preliminary approach to very elaborate studies on intestinal absorption. In these conditions, the nitrogen of amino acids from duodenally-perfused small peptides was absorbed earlier and more rapidly than that from a perfusion of a solution of free amino acids. The amount of nitrogen appearing in the portal vein five hours after perfusion exceeded the perfused amount owing to considerable recycling of endogenous nitrogen.

Amino Acids↗
PubMed1984

Intestinal absorption mechanisms of thyrotropin-releasing hormone.

Intestinal absorption mechanisms of thyrotropin-releasing hormone (TRH) following the oral administration of TRH-tartrate (TRH-T) were studied in animals. When TRH-T was orally administered to rats or beagle-dogs, absorption of TRH showed apparent saturation and decreased with food ingestion. TRH is very stable against gastrointestinal digestive enzymes, homogenized intestine and epithelial cells. First pass effect in the liver was not observed in beagle-dogs. Absorption site specificity was found in rats, namely TRH can be absorbed from only the upper part of the small intestine. A saturation phenomenon was also observed in in situ and everted sac experiments. TRH absorption was inhibited by the existence of oligopeptides and some beta-lactam antibiotics that had been reported to be absorbed by active transport or carrier-mediated transport systems. The transfer of TRH from mucosal to serosal solutions was inhibited by the replacement of medium Na ions by K ions and by the existence of oligopeptides. The transfer rate from serosal side to mucosal side was much slower than that from mucosal side to serosal side. These results suggested that there should be a certain carrier-mediated transport system in the absorption process of TRH.

Animals↗
PubMed1983

In vivo intestinal absorption of manganese in the rat.

The mechanisms of intestinal absorption of Mn in rats and the effects of low-molecular-weight ligands in this process were investigated using an in vivo perfusion system. Segments of either jejunum or ileum were perfused with isotonic solutions containing 0.0125 to 0.1 mM MnSO4 X 7H2O, in the presence or absence of double its concentration of either L-histidine (His) or citrate (Cit). In all cases the absorption of Mn declined with time; for example, in the absence of ligand Mn absorption fell from (means +/- SEM) 16.0 +/- 2.2 at 30 minutes to 2.3 +/- 4.1 pmol/(minute X cm) after 90 minutes of perfusion. Comparable declines occurred both in the jejunum and in the ileum in the presence of His or Cit. The initial absorption rates of Mn, obtained by extrapolation, were higher in the jejunum when His or Cit were present than when no ligands were included in the perfusate [means +/- SD, with His, 66.4 +/- 11.9; with Cit, 79.5 +/- 6.2; none = 17.8 +/- 3.3 pmol/(minute X cm)]. In the ileum, optimum absorption with His was observed between pH 7 and 8. The kinetics of in vivo Mn ileal absorption in the presence of His yielded a Kt of 0.056 mM and an estimated Vmax of 158 pmol/(minute X cm). The coefficient of diffusion was calculated to be 1.5 X 10(-3) cm2/minute. These data are compatible with a high affinity, low capacity, active transport mechanism for Mn in the rat intestine and suggest a limited role for small-molecular-weight ligands associated with both diffusional or active translocation processes.

Animals↗